Once widespread in the grasslands and western basins of North America, by 1987 Black-footed Ferrets were thought to be extinct in the wild. Captive animals were bred in an effort to save the species, and in 1991, some were reintroduced in Montana, South Dakota, and Wyoming. The Ferrets depend on prairie dogs, living in their tunnels and eating them, and the young are born in prairie dog tunnels. Black-footed Ferrets are mostly nocturnal and seldom seen. The best chance of seeing them is in mid- to late summer, after the young begin to be active aboveground.